Absentee parents in picture books

In discussing the classic picture book Are You My Mother? today, an important question was raised. Namely: Why is the bird not concerned about who his father is? The baby bird moves heaven and earth to find his mother, but is completely unconcerned by the absence of his father. Could this book be an early example of positive depictions of single parenting? Is the bird unconcerned because he sees his father solely as an earner and would rather seek nurturing from his mother? Who, the bird should be asking, brought in the worms while mother was warming the eggs? Constantly, the little bird asks, "Are you my mother?" Why does a book written long before the mainstreaming of single parenthood present a baby bird with no father in sight, and no concern for his absence?

NOTE: Don't take the above seriously. If it were meant to be serious, there would be footnotes.